Elastic fluid power plant



G. B. WARREN .Feb. 16, 1937.

ELASTIC FLUID POWER PLANT Filed April 25, 1955 m x 4 m e r Wmww MW w WBA I 5 n W k Patented Feb. 16, 1937 PATENT o FicE ELASTIC FLUID POWERPLANT Glenn B. Warren, Schenectady, N. Y., assignor to General ElectricCompany, a corporation of New York Application April 25, 1933, SerialNo. 667,812

. 12 Claims.

The present invention relates to elastic fluid power plants in whichelastic fluid, for instance, steam or vapor, is produced in an elasticfluid generator and consumed in a consumer. The

,. elastic fluid generator usually comprises a boiler, that is acontainer or containers such as drums and heating tubes in which liquidis heated and evaporated, means including a preheater for supplying andcontrolling the supply of make-up or feed fluid to the boiler, a furnacefor heating the boiler, and means for supplying and controlling thesupply of fuel and air to the furnace. The consumer may comprise anelastic fluid turbine, means for conducting and regulating the flow ofelastic fluid to the turbine, and means including a condenser forreceiving exhaust fluid from the turbine. The means for supplying andregulating the supply of feed fluid to the boiler and the means forsupplying combustible material and air to the furnace may include pumpsand a blower driven by auxiliary motors or prime movers such as elasticfluid turbines receiving drive medium from the boiler.

The object of the present invention is to provide an improvedarrangement for power plants of the type specified whereby the controland regulation of the various apparatus is accomplished in a simplemanner.

For a consideration of what I consider to be novel and my invention,attention is directed to the following description and the claimsappended thereto, in connection with the accompanying drawing.

In the drawing, Fig. 1 represents a power plant embodying my invention,and Figs. 2, 3 and 4 show modifications of the control arrangement of acertain part of the power plant.

In Fig. 1 I have shown by way of example a power plant according to myinvention adapted O to be usedin aircrafts. The elastic fluid generatorcomprises a furnace Ill havingawasing H, and means for supplying fueland air to the furnace. The fuel supply means include a source of fuel,such as a tank l2 containing oil, a conduit l3 connected to the fueltank I2, a fuel pump i4 and a conduit I5 for conducting the fuel to aburner i6 located within the furnace. The air supply means include achannel or suction conduit Ill and a blower 18 having a dischargeconduit connected to the furnace. The pump it is preferably a positivedisplacement pump. Both the pump l4 and the blower l8 are driven by acommon motor or prime mover, in the present instance shown as anauxiliary turbine i9 having a shaft connected to the-pump l4 and theblower l8 by gears 2| and 22 respectively.

In accordance with my invention I proportion the blower I8 including thesuction or inlet conduit I! so that for a certain condition an amount 5of air is supplied to the furnace which is sufiicient to maintain thecombustion of the fuel such as oil supplied by the pump M to thefurnace. By a certain condition is meant a certain barometric pressureand the drop in pressure in the suction conduit which depends upon therelative velocity of the airplane with respect to the current of airoutside the inlet or suction conduit ll. We may assume that the speed ofthe motor or auxiliary turbine l9 changes in accordance with the demandfor elastic fluid output in the elastic fluid generator. The means foraccomplishing this will be described later. With this assumption thepump I 4 and the blower l8 serve to supply an amount of fuel and air for20 maintaining the combustion, which amount under the above mentionedcertain condition is sufficient to generate the necessary elastic fluidat varying loads. To obtain the right proportioning between the fuel andair supply at other conditions, I provide in accordance with myinvention regulating means for regulating the flow of air in the inletor suction conduit ill of the blower in response to changes inbarometric pressure, changes in the flow of air in the suction conduiti1, and changes in the flow of fuel in the fuel conduit 53. The controlarrangement comprises a nozzle 23 in the conduit l3, a nozzle 24 in theconduit ii, flow responsive means 25 and 26 connected .to the nozzles 23and 24 respectively, a barometric pressure responsive device 2'! and avalve 28 shown as a butterfly valve in the air suction conduit ll. Morespecifically, the barometric pressure responsive device has a bellows 29with a lower portion. fixed to a support 30 and a top portion connectedto one end of a fulcrumed lever 31 which has its other end connected bymeans of a spring 32 to a link 33 for moving the valve 28. A spring 34provided between the bottom and top portions of the bellows and thespring 32 prevent the bellows from collapsing.

With this arrangement a decrease in barometric pressure which occurswhenever the airplane increases its altitude causes expansion of thebellows whereby the lever 3| is turned in clockwise direction and causesdownward movement of link 33, to the effect that valve 28 opens andpermits an increased Volume of-air to maintain constant the amount orweight of air delivered by the blower. By amount or weight of air ismeant the weight of air delivered during a certain period of time. Theflow-responsive device comprises a casing having an upper half and alower half with a diaphragm 36 therebetween. The central portion of thediaphragm is connected to a stem 3'! which has its lower end pivoted toan intermediate point of a lever 38 turning about a fulcrum 39 and beingconnected to the link 33. The upper casing half communicates with theconduit l3 ahead of the nozzle 23 by means of a pipe 40. The lowercasing half communicatees with the conduit l3 behind. the nozzle 23 asregards the direction of flow through the conduit I 3 by means of a pipe4|. The flow-responsive device 26 is similarly arranged. It comprises acasing 42 with a diaphragm 43 connected to the lever 38 by a stem 44 andpipes 45 and 46 for connecting the lower and upper casing halvesrespectively to the conduit ll ahead and behind the nozzle 24respectively as regards the direction of flow through the conduit 11.The flow-responsive device 26 controls the flow of air through theconduit I! in response to changes in pressure drop in conduit 24 causedby changes in the velocity of air through the conduit 24, morespecifically by changes of the relative speed between the conduit 24 andthe current of air outside the conduit. As stated above, the blower I8is dimensioned to supply as nearly as possible, under certainconditions, an amount of air sufficient to maintain the propercombustion of the fuel supplied by the pump M. In the case of anairplane power plant it is preferable to make the arrangement so that atnormal speed of the airplane, which may be 100 miles per hour, the pumpsupplies suflicient air to the furnace for maintaining combustion of thefuel supplied by the fuel pump l4. The inlet of conduit l! is locat d inforward direction, so that air is forced into the conduit during flightof the airplane, the amount of air flowing into the conduit increases asthe speed of the airplane increases, and vice versa. With thisarrangementv an increased speedcauses an increased flow of air throughthe suction conduit I! which without the provision of special controlmeans would cause an excessive amount of air being supplied to thefurnace. With the arrangement of the flow-responsive device 26 anincreased flow of air in the conduit ll, due to an increased relativevelocity between the conduit and the current of air, causes thediaphragm 43 in casing 42 to be forced upward, owing to the increasedpressure drop in the conduit ll, whereby the lever 38 turns in clockwisedirection about its fulcrum and effects closing of the valve 28 in theconduit ll. Thus the amount of air conducted through the conduit I1 ismaintained constant;

In the arrangement shown in the drawing, the stems 31 and 44 of theflow-responsive devices are arranged in alinement so that no springmeans are needed for balancing the pressures acting on the diaphragms 36and 43. The pressures acting on the two diaphragms balance each other.By properly dimensioning the diaphragms or using different materials forthe diaphragms, any desirable characteristic of the-control arrangementis obtained.

If the flow of fuel through the conduit 23 changes, owing, for instance,to the variation of the fuel head in tank 12, the flow-responsive device25 automatically causes positioning of the valve 28 in terms of changein flow of fuel. If, for example, the flow of fuel increases, thediaphragm 36 of the flow-responsive device is moved downward and causesthrough the lever 38 and the link 33 opening movement of the valve 28,resulting in an increased flow of air. If the flow of fuel through theconduit 23 decreases, a similar action takes place with the difierentparts moving in opposite direction and resulting in closing of the valve28.

The two flow-responsive devices 25 and 26 and the barometricpressure-responsive device 21, together with the valve 28, represent insubstance means for automatically controlling the supply of air to thefurnace in response to changes in fuel supply, changes in relative speedbetween the conduit I! of the airplane and the current of air,

and in response to changes in barometric pressure.

In Fig. 2 I have shown a modification of this automatic controlarrangement. Like parts are designated with like reference characters.The stem 33 of. the valve 28 is biased in this arrangement in upwarddirection by means of a spring 41, and carries at its upper end a roller48 bearing against the cam surface of a cam 49 fastened to a shaft 50.Adjacent the cam is a pinion 5| fastened to the shaft 50 and meshingwith a rack 52 Connected to the rack 52 is a piston 53 movable in acylinder 54 and biased towards the left by a spring 55. The cylinder 54has a lefthand portion connected by means of. a pipe 56 to the inlet ofthe nozzle 23 and a right-hand portion connected to the outlet side ofsaid nozzle by means of a pipe 51. The left-hand end of the rack 52 isconnected to a barometric pressure responsive device including a bellows58. If. with this arrangement the flow of fuel increases, the piston 53in cylinder 54, which in substance represents a flow-responsive device,is moved towards the right and thereby causes the cam 49 to rotate inclockwise direction, resulting in an opening movement of the valve 28and accordingly an increased flow of air in the conduit I1. If thebarometric pressure increases, the bellows 58 collapses somewhat andcauses the rack 52 to move to the left, resulting in a closing movementof the valve 28. Similar operations take place with movements inopposite directions if the fiow of fuel in the fuel conduit 23, and thebarometric pressure decrease. The device shown in Fig. 2 does notinclude any means for controlling the flow of air in response to changesin the relative speed between the conduit I1 and the current of airoutside the conduit.

In both arrangements of Fig. l and Fig. 2 the control means for thevalve 28 are connected together, that is, in Fig. l the twoflow-responsive devices 25 and 26, as well as the barometric pressureresponsive device 29 are connected to a common lever 38, and in Fig. 2.both the flow-responsive device 53, and the barometric pressureresponsive device 58 are rigidly connected to the rack 52.

In Figs. 3 and 4 I have shown arrangements in which the three controldevices may act independently from each other, that is, movement of theone has no direct effect and particularly does not exert a biasing forceon the other. This is accomplished in the arrangement shown in Fig. 3 byproviding the air inlet conduit I! for the blower with three branches60, GI and 52, of which each includes a-valve means 63, 64 and 65respectively. The valve 63 in branch 66 is controlled by a barometricpressure responsive device 66. The valve 64 in branch 6| is controlledby a flow-responsive device 61 connected to the fuel supply conduit 23corresponding to the con- Cir duit 23 in Figs. 1 and 2. The valve 65 inbranch 62 is controlled by a flow-responsive device 69 including pipes10 and H connected to the nozzle 24 in the conduit H. Theflow-responsive devices 61 and 69 are similar to the flow-responsivedevices 25 and 26 in Fig. 1 except that each includes a biasing spring12 and 13 respectively.

During operation, a decrease in barometric pressure causes expansion ofthe bellows 66 whereby the valve 63 is opened and the flow of airthrough the branch 60 is increased. Similarly, an increase of flow offuel through conduit 23 causes the diaphragm of. the flow-responsivedevice 61 to be forced downward to effect opening of the valve 64. Anincrease in the flow of air through the conduit I'I, due to a change inrelative speed between the conduit H and the current of air, causes theflow-responsive device 69 to close the valve 65.

In Fig. 4 I have shown an arrangement in which the valve 28 in thesuction conduit 11 of the blower is connected to a floating lever 13 Thelefthand end of the floating lever is pivoted to the bellows 14 of abarometric pressure responsive device 15 and the right-hand end of thefloating lever 13 is linked to an intermediate point of another floatinglever 16. The rightehand end of the latter is connected to a device 11responsive to the flow of fuel in the conduit l3, and the left-hand endof the floating lever 16 is connected to a device 18 responsive to theflow of air in the conduit ll. This is a preferable arrangement becausethe control of each device is independent from the positions of theother devices. During operation, an increase in barometric pressurecauses the left-hand end of lever 13 to move up, the lever thereby turnsabout its right-hand end as a fulcrum and causes closing of the valve28. An increase in flow of fuel in conduit I3 causes the right-hand endof the lever 16 to move down, the lever 16 thereby turns about itsleft-hand end as a fulcrum and due to its connection with lever I3causes the latter to turndown about its left-hand end as a fulcrum,

resulting in opening of the valve 28. A decrease in flow of air throughconduit I1 causes in a similar manner through the flow-responsive deviceIS an opening movement of the valve 28.

The mechanism so far described represents an arrangement forautomatically controlling the supply of fuel and air to a furnace.Located in the furnace are containers or he'aders l9 and 89 connected bytubes ill for containing liquid such as water or mercury to be heatedand evaporated. Heat is transmitted to the containers and the tubes byradiation and conduction. The fire gases escape through a flue 82 whichhas an opening in rearward direction of the aircraft. The elastic fluidproduced in the boiler is supplied to a consumer shown as an airplaneturbine or main turbine 83 driving a propeller 89 through theintermediary of a reduction gearing 65. A turbine of this type is morefully disclosed in my copending application Serial No. 632,932, filedSeptember 13, 1932. The path of fluid between the boiler and the turbineis defined by a conduit 86, a chest ill and a conduit 89 between thechest and the inlet of the turbine. The turbine has an exhaust conduit8.9 connected to a condenser 90 for condensing the exhaust elastic fluidof the turbine.

The condensate is returned to the boiler through the intermediary of apreheater which forms a part of the elastic fluid generator. In thepresent instance I have shown three preheaters 9|, 92 and 93. Thecondensate is pumped through the preheaters into the boiler. This isaccomplished by the provision of two pumps 94 and 95. The suctionconduit of pump 94 is connected by means of a conduit 96 to a well 91which receives the condensate from the condenser 9D. The dischargeconduit of the pump 94 is connected by a conduit 98 to the inlet orsuction conduit of the pump and a discharge conduit 99 of the latter isconnected to the preheater 9|. The two pumps and the three preheaters aswill be readily. seen are connected in series. The preheater 93 which isthe last preheater as regards the direction of flow of fluid through thepreheaters discharges into the lower header 80 of the boiler through aconduit I20 including a check Valve l2l. The boiler feed liquid passingthrough the preheater 93 is heated by means of elastic fluid extractedfrom an intermediate stage of the turbine. In the present instance Ihave shown a conduit I09 including a check valve llll for conductingelastic fluid from an intermediate turbine stage to the preheater 93.Similarly the fluid passed through the preheater 92 is preheated byelastic fluid extracted from a lower stage of the turbine by a conduitI02 including a check valve I03. The heating fluid supplied to thepreheater 93 is drained therefrom and supplied to the preheater 92through a conduit I04 including a drip valve or an orifice I05, and theheating fluid supplied to the preheater 92 together with the condensatedheating fluid received from the preheater 93 is conducted to thepreheater 9| through a conduit I06 including a drip valve or an orificeI07. The heating fluid is drained from preheater 9! through a conduit-I08 including a drip valve or an orifice I09 and conducted into thesuction conduit 96 of the feed pump 94. No heating fluid is directlysupplied from the turbine to the preheater 9!. This preheater receivesheating liquid through the drip valve I01 from the preheaters 92 and 93and therefore may be termed a drip preheater. The drip valves ororifices are provided to allow only condensate to flow out from thepreheaters.

The pumps 96 and 95 for forcing make-up or boiler feed liquid into theelastic fluid generator are driven from the shaft 29 of the auxiliaryturbine l9 through gearings H9 and I! ll respectively. Preferably Iprovide positive displacement pumps for feeding liquid into the elasticfluid generator whereby the amount of boiler feed liquid delivered bythe pumps is primarily determined by the speed of the pumps which inturn is fixed by the speed of the motor or auxiliary turbine 09.Assuming again that the speed of the turbine i9 is regulated in responseto demand for elastic fluid, then the supply of boiler feed liquid isregulated in response to the demand for elastic fluid from thegenerator. In addition I provide a control arrangement for regulatingthe feed water supply in response to changes in temperature of theelastic fluid in the boiler. This is accomplished by the provvision of abypass H2 between the discharge and the suction conduits of the pump 95and 2.

valve H3 in the bypass which is moved in response to temperature changesof the generated elastic fluid. The valve H3 has a stem connected to adiaphragm H5 of a pressure rcsponsive device. The valve is biasedtowards open position by a spring H6 surrounding the valve stem and theright-hand casing half of the pressure responsive device has a conduitH1 with a sealed end H8 projecting into a chest II9 of the boilerdischarge conduit 86.

If during operation the temperature of the elastic fluid increases itcauses expansion of a gas such as air entrapped in the conduit I I1 andthe left-hand casing half of the pressure responsive device, to theeffect that the valve H3 is moved towards closed position. Thisdecreases the amount of liquid which is bypassed between the dischargeconduit 99 and the suction conduit 98 of the pump 95 and accordinglyincreases the amount of boiler feed liquid delivered from the dischargeconduit 99 to the preheater. The bypass I I 2 together with thetemperature responsive device represent a means for automaticallymaintaining constant the temperature of the elastic fluid in the boiler,and the pumps together with the bypass and the temperature responsivedevice represent means for automatically regulating the amount of feedliquid to the .boiler in response to the demand for elastic fluid. Thelast named means together with the arrangement for supplying andcontrolling the supply of fuel and air to the furnace represent insubstance means for automatically controlling the amount of elasticefluid generated in the boiler in terms of demand for elastic fluid.

The demand for elastic fluid depends upon a number of factors, primarilythe speed of the propeller. The flow of elastic fluid to the turbine isregulated by means of a valve I22 connected to a fulcrumed lever I23which in turn is connected by means of a link I24 to one arm of a bellcrank lever I25 having its other arm connected by a link I 26 to anintermediate point of a fulcrumed hand lever I2'I. Movement of the handlever to the left effects downward movement of link I24 and openingmovement of valve I22 which thereby admits an increased flow of elasticfluid to the turbine. The increased flow of fluidto the turbine, thatis, the increased demand for elastic fluid generated in the boilernecessitates an increased supply of fuel and air to the furnace and alsoan increased supply of make-up liquid to the boiler. This isaccomplished by increasing the speed of the motor or auxiliary turbineI9, in the present instance, by increasing the amount of elastic fluidsupplied to the turbine I9. The auxiliary turbine has an inlet conduitI28 receiving elastic fluid from a lower extraction stage of the turbinethrough a conduit I29 which in substance forms a continuation of theconduit I02. The conduit I29 includes a check valve I30 and has itslower end connected to conduit I 28 by means of a conduit I 3I includinga valve I32. When the valve I32 is "fully opened, live elastic fluid maybe supplied to the auxiliary turbine through a conduit I33 having oneend connected to the joint between the conduits I 28 and I3I and itsother end to the chest 81. A valve I34 for regulating the amount of liveelastic fluid supplied to the auxiliary turbine is provided within thechest 81. The stem I35 of the valve I34 is pivoted to the right-hand endof a floating lever I36 which has its left-hand end connected to thestem I31 of the valve I32. The valve I34 is biased towards closedposition by means of a spring I38. The downward movement of the stem I31of the valve I32 is limited by an adjustable stop I39. Connected at anintermediate point of the lever I36 is a stem I40 to which is fastened apiston I4I slidably arranged in a dashpot I42. The piston has an openingI43 which permits communication and displacement of a fluid contained inthe upper portion and the lower portion of the dashpot. The dashpot ispivoted to a fulcrumed lever I 44 which in turn is connected to thefulcrumed lever I23 by. means of a link I45. Connected to the piston isa pressure responsive device I46 comprising a casing I41, a bellows I48having a top portion fastened to the casing I41 and a bottom portionfastened to a stem I49 which in substance forms an extension of the stemI40. The bellows is biased in downward direction by a spring I50surrounding the stem I49. The pressure responsive device is subject tothe pressure of the elastic fluid in the boiler through a pipe I5Ibetween the casing I41 and the discharge conduit 86 of the boiler.

During operation, the opening movement of the lever I27, indicated by anarrow, causes downward movement of the link I24'and, as explained above,opening of the turbine admission valve I22 whereby the flow of elasticfluid to the turbine increases. The downward movement of the link I24causes at the same time a downward movement of the left-hand end offulcrumed lever I44. The dashpot I4I, together with the piston I43,thereby are moved downward owing to the fact that the comparativelyshort period of time during which the movement of the fulcrumed leverI44 takes place does not permit a substantial I displacement of fluid,which may be oil, between the upper and lower part of the dashpot. Inother words, for short or sudden movements the dashpot acts like a rigidconnection between the lever I44 and the piston I43. The movement of thelever I36 causes, at first, opening movement of the valve I32 whichpermits an increased supply of extraction elastic fluid to the auxiliaryturbine. The valve I34 is retained in closed position by the biasingspring I38 until the valve I32 is fully opened, that is, until theleft-hand end of lever I36 engages the adjustable stop I39. In thisposition further downward movement of the stem I40 causes opening of thevalve I34 against the biasing force of the spring I38 to permit liveelastic fluid being supplied to the auxiliary turbine.

Thus the valves I32 and I34 represent means for controlling theauxiliary turbine or the motor IS in response to movement of theregulating means, that is the valve I22 for the main turbine. Theauxiliary turbine or motor I9, together with the control means for thisturbine, the pumps, and the blower driven by said turbine. represent ameans for automatically regulating the generation of live elastic fluidin the elastic fluid generator in response to demand for live elasticfluid, or, from another viewpoint, in response to movement of theregulating means for the main turbine.

The pressure responsive device I46 serves to adjust the regul"ting meansfor the auxiliary turbine in response to pressure conditions in theboiler. If the demand for elastic fluid increases, one or both of thevalves I32 and I34 are opened to increase the supply of elastic fluid tothe auxiliary turbine I9. This causes an increased supply of fuel andair to the furnace and feed water to the boiler. Whereas the increaseddemand for elastic fluid causes, at first, a drop in pressure in theboiler, the increased supply of fuel to the furnace thereafter causes a,rise in pressure. The rise in pressure effects through the pressureresponsive device I46 a repositioning of one or both of the valves I 32and I 34 to maintain substantially constant the power supply to theauxiliary turbine I9. More specifically, the rise in pressure causes thebellows to collapse against I49, together with the piston I43 moveupward and effect closing movement of one or both of the valves I32andl34. In case the valve I34 is already closed, the valve I32 will befurther closed and if valve I34 is partly opened then this valve willfirst be closed and as soon as it has been shut the valve I32 may bepartly closed. The closing movement of the valves takes place slowlyowing to the provision of the dashpot. The dashpot cylinder in this caseremains stationary whereas the piston I4I moves within the I dashpot,causing displacement of fluid between the upper and lower portionsthereof through the opening I43 in the piston MI.

The auxiliary turbine I9 has been shown as having an exhaust connectedby means of conduits I52 and I53 to the exhaust conduit 89 of the mainturbine 83. The-elastic fluid generator is provided with a blow-offvalve I54 in the discharge conduit 86. If the pressure in the boilerexceeds a predetermined value, the blow-off valve opens against thebiasing force of a spring I55 to permit relieving of the elastic fluidpressure. The elastic fluid discharged through the blowoff valve isconducted through a conduit I56 which forms a continuation of theconduit I53 into the exhaust conduit 89 of the turbine.

Summarizing, a few of the important features of the operation of myelastic fluid power plant: In order to decrease the output of theturbine, to lower for instance the speed of an aircraft, the lever I2!is moved towards closing position, that is, towards the right. Thiseffects closing of the turbine valve I22 and accordingly a decreasedsupply of elastic fluid to the tur- Y bine, and simultaneously a closingmovement of one or both of the valves I34 and I32 for the auxiliaryturbine whereby the speed of the latter decreases and automaticallyefiects a decreased gen- .eration of elastic fluid in the boiler. Thepressure in the boiler thereby decreases and eflects through thepressure responsive device I46 a repositioning of the regulating meansfor the motor or auxiliary turbine I9 to maintain substantially constantthe output of the latter.

A change in boiler temperature through the temperature-responsive deviceII5-III and the bypass I 02 for the feed pumping means automaticallycauses a charge in the supply of boiler feed liquid to the elastic fluidgenerator.

If the relative speed between the power plant and the curent of air, orthe supply of fuel to the furnace, or the barometric pressure, changes,then the flow of air in the suction conduit of the -blower isaccordingly automatically changed under action of the flow-responsivedevices 25 and 26 and the barometric pressure-responsive device .39, sothat under any condition the supply of air to the furnace isproportioned to maintain proper combustion of the fuel supplied to thefurnace.

The entire operation of the elastic fluid power plant is automatic. Allthat is necessary to change the operation is to move the lever I21towards opening or closing position. Movement towards opening positioncauses an increased load output of the turbine and towards closingposition a decreased load output. The complete automatic operation ofthe power plant is of particular significance in case the power plant isused in connection with an aircraft because it does not need theattention of a special operator but can be handled by the pilot of theaircraft. The le- 'ver I21 which is the main controlling lever for theentire power plant may be easily arranged in reach of the pilot.Movement of this lever effects a. change in the supply of elastic fluidto the main turbine. This change rapidly causes an automatic positioningof the various regulating devices in accordance with the changed demandfor load output.

Having described the method of operation of my invention, together withthe apparatus which I now consider to represent the best embodimentthereof, I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In an elastic fluid generator, the combination of a furnace, meansincluding a pump for supplying fuel to the furnace, means including ablower having a suction conduit for supplying air to the furnace tomaintain combustion, valve means in the suction conduit, andmeans forpositioning the valve means in response to the barometric air pressure,the velocity of the current of air outside the suction conduit, and theflow of fuel to the furnace.

2. In "a power plant, the combination of an elastic fluid generatorcomprising a furnace, a boiler, a fuel pump and a boiler feed pump, anauxiliary turbine for driving said pumps, a main turbine connected tothe boiler, means for regulating the supply of elastic fluid to the mainturbine, conduit means for conducting elastic fluidfrom an intermediatestage of the main turbine and from the boiler to theauxiliary turbine,and valve means in said conduit means connected to the regulating meansfor the main turbine.

3. In a power plant, the combination of an elastic fluid generatorcomprising a furnace, a boiler a fuel pump and a boiler feed pump, anauxiliary turbine for driving said pumps, a main turbine connected tothe boiler, means for regulating the supply of elastic fluid to the mainturfor controlling the valve means in response to changes of fluidcondition in the boiler.

i. In a power plant, the combination of a boiler, means including amotor for regulating the generation of elastic fluid in the boiler, amain turbine connected to the boiler, an admission valve for the mainturbine, means for controlling the admission valve, means forcontrolling the motor in response to movement of said admission valveand pressure changes in the boiler,

5. In a power plant, the combination of a boiler for generating elasticfluid, a main turbine connected to the boiler, valve means forcontrolling the supply of elastic fluid to the main turblue, and meansfor'automatically controlling the generation of elastic fluid in theboiler comprising an auxiliary turbine, a conduit including a valve forconducting live elastic fluid to the auxtermediate stage of the mainturbine to the auxiliary turbine, a dashpot having a pistonconnected tothe two last named valves and a cylinder connected to-the main turbinevalve means, and

a device responsive to changes in fluid condition of the live elasticfluid in the boiler connected to the dashpot piston.

6. In a power plant for an aircraft, the conibination of a boiler, aturbine for driving a propeller receiving elastic fluid from the boiler,a condenser for the turbine, means including a preheater receivingcondensate from the condenser and heating fiuid from an extraction stageof the turbine for automatically supplying condensate to the boiler inresponse to the demand for elastic fluid and temperature changes in theboiler, a motor for operating the last named means, and means forcontrolling the motor in response to the demand for elastic fiuid andthe pressure of elastic fluid in the boiler.

'7. In a power plant, the combination of an elastic fluid generatorcomprising a boiler and auxiliaries, a main turbine connected to theboiler, said auxiliaries including an auxiliary turbine, a first conduitincluding a first valve between an extraction stage of the main turbineand the auxiliary turbine, a second conduit including a second valvebetween the boiler and the auxiliary turbine, a main valve for the mainturbine, and

a mechanism for transferring movement of the main valve to said firstand second valves.

8. In a power plant, the combination of an elastic fluid generatorcomprising a boiler and auxiliaries, a main turbine connected to to theboiler, said auxiliaries including an auxiliary turbine, a first conduitincluding a first valve between an extraction stage of the main turbineand the auxiliary turbine, a second conduit including a second valvebetween the boiler and the auxiliary turbine, a main valve for the mainturbine, a mechanism for transferring movement of the main valve to saidfirst and second valves, and means for normally biasing the second valvetowards closing position and permitting opening thereof in a certainposition of the first valve.

9. In a power plant, the combination of an elastic fiuid generatorcomprising a boiler and auxiliaries,, a main turbine connected to theboiler, said auxiliaries including an auxiliary turbine, a first conduitincluding a first valve between an extraction stage of the main turbineand the auxiliary turbine, a second conduit including a second valvebetween the boiler and the auxiliary turbine, a main valve for the mainturbine, a mechanism for transferring movement of the main valve to saidfirst and second valves, and means for positioning the first and secondvalves in response to changes in elastic fluid conditions in the boiler,said means being independent from the transferring mechanism.

10. In an elastic fiuid generator, the combination of a furnace, meansincluding a first conduit for supplying fuel to the furnace, other meansincluding a second conduit having a plurality of parallel branches forsupplying air to the furnace, a valve in one of the branches, means forcontrolling the valve in response to fiow of fuel in the first conduit,another valve in another branch, and other means for controlling theother valve in response to changes of air condition in the secondconduit.

11. In an elastic fiuid generator, the combination of a furnace, meansincluding a pump for supplying fuel to the furnace, means including ablower having a suction conduit for supplying air to the furnace tomaintain the combustion, valve means in the suction conduit, means forpositioning the valve means comprising a barometric air pressureresponsive device, and other devices responsive to the fiow of fuel andthe flow of air, and a mechanism for connecting the devices to the valvemeans to permit independent control of the valve means by each of thedevices.

12. In a power plant, the combination of an elastic fluid generatorcomprising a furnace, a boiler, a fuel pump, a boiler feed pump, anauxiliary turbine for driving said pumps, a main turbine connected tothe boiler, means for regulating the supply of elastic fluid to the mainturbine. conduit means for conducting elastic fluid from an intermediatestage of the main turbine to the auxiliary turbine, and other conduitmeans including a valve for temporarily conducting elastic fiuid fromthe boiler to the auxiliary turbine in response to sudden increases indemand for load output from the main turbine.

GLENN B. WARREN.

